Directional solidification furnaces are used, for example, to produce multi-crystalline silicon ingots. The furnace has a crucible into which raw silicon is placed. The crucible is supported by a structure that adds structural rigidity to the crucible. The crucible is disposed within a containment vessel that forms part of the furnace and seals the crucible from the ambient environment.
During use, the raw silicon is melted and then cooled at a controlled rate to achieve directional solidification within the resulting ingot. The controlled rate of cooling is established by any combination of reducing the amount of heat applied by the heaters, movement of or opening of a heat vent in insulation surrounding the crucible, and/or the circulation of a cooling medium through a heat exchanger disposed adjacent the crucible and/or the crucible support. The ingot solidifies in the region closest to the cooler side of the crucible and proceeds in a direction away from the cooler side of the crucible.
The efficiency and complexity of heat exchangers used to transmit heat away from the crucible during solidification of the ingot is a concern. As the size of crucibles has increased, the size and complexity of heat exchangers has increased as well. There exists a need for a more efficient and less complex heat exchanger for use in directional solidification furnaces.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.